WisDOT preparing to open two major Zoo Interchange system ramps

Mike Burns, a construction project manager with the Wisconsin Department of Transportation, looks over the Zoo Interchange project while standing atop a connector ramp on Friday. The ramp, which is scheduled to open next week, will connect traffic from eastbound Interstate 94 to northbound Interstate 41. (Staff photos by Kevin Harnack)

Navigating the Zoo Interchange will be much easier during the Memorial Day weekend, thanks to the scheduled opening of two system ramps.

Department officials said they are on track to open the ramp connecting eastbound Interstate 94 to northbound Interstate 41 on Wednesday. A day later, the ramp connecting southbound Interstate 41 with the eastbound lanes of I-94, as well as the Wisconsin Avenue bridge going over I-41, will open.

The three openings will come as the most significant milestones reached this season amid work on the Zoo Interchange’s second core phase — a $300 million, three-year project.

“This is a big milestone for this project to get these ramps open,” Jason Roselle, WisDOT construction supervisor, said on Friday atop the interchange’s ramp linking I-94 east to I-41 north.

Work on the Zoo Interchange project’s first core phase — a nearly $200 million let — wrapped up in June last year. The second phase is expected to be complete by late summer 2018.

Freeway traffic and the Milwaukee skyline are visible on the horizon from atop a connector ramp between Interstate 94 and Interstate 41 in the Zoo Interchange on Friday. WisDOT is scheduled to open two ramps next week as the massive project hits more milestones.

The Zoo Interchange is among the largest projects in WisDOT’s history. The nearly 50-year-old interchange is already the most used in the state.

And it’s likely to only get busier. Its daily traffic count — now at 350,000 vehicles — is expected to increase to 410,000 vehicles a day by 2035.

The work has meant that traffic for months has had to take detours onto smaller highways and local streets to go to and from the various freeways that converge in the area. With the ramp re-openings next week, drivers will again be able to use the interchange to make those connections. The resulting traffic reduction should be especially welcome to travelers during the state’s tourism season, which generally starts with Memorial Day weekend.

With that in mind, “staying on deadline was critical,” Roselle said, adding that this year’s mild winter helped keep things moving forward.

The interchange’s new configuration is far better suited to current traffic counts than was the original design, which dated to the 1960s. Among the features to help traffic flow are various “collector” roads that will take vehicles out of mainline traffic before they reach their exit ramps, explained Bob Gutierrez, an engineer at WisDOT.

Once finished, the entire interchange project will have 9 miles of reconstructed freeway, 3.5 million miles of steel rebar, 100,000-plus cubic yards of concrete, more than 100 retaining walls and 73 bridge structures. WisDOT engineers estimate it will be 75 years before the Zoo Interchange needs to be rebuilt again.

One comment

Remember, too, that the original Zoo Interchange was designed as it was in the 1960s in anticipation that the rest of the then planned Milwaukee metro freeway system, especially the Park West and Stadium Freeways, would be built. Had they been built as planned, for example, the SB to EB and WB to NB ramps would only need to be one lane each. Its overall traffic load would also be far lower than it is today.